The present invention relates in general to a fire and smoke detector, and more particularly, to a combination detector that combines in a single unit both optical and ionization forms of detection.
Each form of detection has its own range of sensitivities. For example, optical detectors are more responsive to larger particles of combustion while ionization detectors are more sensitive to smaller sub-micron particulates. Gas-type detectors respond primarily to hydro-carbon gases and are generally insensitive to particulates.
Thus, one of the advantages of the detector of this invention is its greater spectrum of sensitivity. In this way with a combination detector, virtually all major fire hazards are covered.
Accordingly, one object of the present invention is to provide a combination detector including both optical and ionization detection sections.
Another object of the present invention is to provide a combination detector that is not expensive and that has relatively few components so that it can be accommodated in a relatively aesthetically appealing unit.
Another object of the present invention is to provide a combination detector that provides both a pre-alarm condition and a full alarm condition.
Still another object of the present invention is to provide a combination detector that distinguishes between certain different alarm conditions such as a pre-alarm and a full alarm condition or detection at one or more than one detector.